The present invention relates to a probe chip for assaying various detection items about objects to be detected, such as DNA, RNA and proteins, at a time (i.e., a many item-detecting sensor), and in particular to a polynucleotide probe chip for assaying DNA and a polynucleotide detection method using the same.
The genome project rapidly approaches the stage of functional genomics. DNA analysis has been clarifying the mechanism of livings and living phenomena. And the DNA analysis has been used for diagnosis of the many diseases. It is effective for understanding living phenomena and examining the effect of genes that the situation of expression of the genes is examined. As a high-powered means, a DNA probe array or a DNA chip wherein a great deal of DNA probes are divided depending on each kind thereof and fixed on the surface of a solid starts to be used. As a method for preparing this DNA chip, there are known a method of using photochemical reaction and lithography, which is widely used in the semiconductor industry, to synthesize oligomers having a designed sequence, one base by one base, on many cells divided up to areas (prior art 1: Science 251, pp. 767-773 (1991)); a method of planting a DNA probe one by one in every area (prior art 2: Proc. Natl. Acad. Sci. USA 93, pp. 4913-4918 (1996)); and the like. In order to increase the amount of probes fixed on a chip, a method is contrived wherein an acrylamide gel film is formed on a chip and probes are fixed on this gel (prior art 2). As a method for fixing DNA probes used in a DNA probe chip, there are known a method of using the bonding of biotin and avidin or fixing DNA probes on the surface of gold (Au) through a SH residue (prior art 3: Biophysical Journal 71, pp. 1079-1086 (1996)); a method of fixing DNA probes on the surface of glass (prior art 4: Analytical Biochemistry 247, pp. 96-101 (1997)); a method of fixing DNA probes on an element matrix of acrylamide gel applied on the surface of glass (prior art 2), and the like.